1. Field of the Invention
The present invention relates to a transfiective liquid crystal display device, and more particularly to an IPS-type transflective liquid crystal display device.
2. Description of the Related Art
A transfiective liquid crystal display device which includes a transmissive part and a reflective part within one sub pixel has been used as a display of a portable equipment.
Such a transflective liquid crystal display device adopts a vertical electric field method in which liquid crystal is sandwiched between a pair of substrates, and an electric field is applied to the liquid crystal in the direction perpendicular to planar surfaces of the pair of substrates thus driving the liquid crystal. Further, to match characteristic of a transmissive part and a reflective part to each other, a step is formed between the transmissive part and the reflective part, and a phase difference plate is arranged between a polarizer and a liquid crystal layer.
As the liquid crystal display device, there has been known an IPS-type liquid crystal display device, wherein pixel electrodes (PIX) and counter electrodes (CT) are formed on a same substrate, and an electric field is applied between both electrodes thus rotating the liquid crystal within a plain of a substrate thus controlling a contrast. Accordingly, the IPS type liquid crystal display device has a characteristic that a contrast of a displayed image is not inverted when a screen is viewed in the oblique direction.
To make use of this characteristic, a technical concept which constitutes a transflective liquid crystal display device using such an IPS-type liquid crystal display device has been proposed in a following patent document 1 or the like, for example.
Here, as a prior-art document relevant to the present invention, the following is named.
[Patent document 1] JP-A-2003-344837